(In the Baker Street drawing room of Britain's most celebrated expert in not locking himself into luggage)

Faulding (reading the crime pages of the Times) : Ah, Watson, if I'm not very much mistaken, here is a rather curious case that will make full use of the very specific faculties I have honed over the years. We must prepare the hold-all at once!

et ceteras...

(Meanwhile in another drawing room, that of James de Quincey, Britain's most celebrated forensic escapologist)

He was originally destined to be an origami expert but developed an allergy to paper so start to use himself. Accidentally locked himself into his briefcase after a particularly good session. The rest is history.

Did I miss something here? Why do they suspect that he may have trained himself to be able lock himself in a holdall in an empty bath?...told the inquest that locking the bag was a skill that would have required training but that once a person had done it, they could not get out.
But he would not rule out that it was possible, adding: "There are people around who can do amazing things and Mr Williams may well have been one of those persons."
Amazing, pointless and ineviatably fatal.